Pillow blocks, also known as plummer blocks, are a kind of bearing housing. They have a re-lubrication facility and can be used with either oil or grease lubrication. The housing material for a pillow block is typically made of cast iron or cast steel. A standard plummer block may include:
- A split plummer block design allows for easy mounting and dismounting of pre-assembled shafts.
- Sealing options such as V-ring seals, labyrinth seals or heavy-duty taconite seals.
- Case end covers are often available.
- Multi relubrication points are provided to ensure re-lubrication of the bearing depending on orientation
- Housing are supplied with spacer rings in order to provide axial location. Those can be ommitted for “free end” axial front.
The upper and lower housings can be assembled together at higher accuracy thanks to ball-knocksystem using steel balls. Also, the upper cover can be removed easily. Designed for greater mechanical strength, most plummer blocks are manufactured under a strict quality control program. To suit the intendedapplication, it can be made of either spheroidal graphite cast iron(ductile cast iron) or cast steel.
There is, however, a slight difference betweenn a Plummer Block and pillow block. Pillow Block Bearings are mostly used in less industrialized environments while Plummer Blocks are used where high performance and high load capacity is required. So that should help you out when you’re searching for the right product. There is a large range of manufacturers and suppliers online, but as is always the case, you should put a great deal of thought and consideraiton into your final decisio, choosing the right product for your needs. It’s also important to understand that plummer blocks are used more in scenarios where alignment is essential and preferred over ball or roller bearings that are used in the blocks. They are also used as support to long shafts during coupling with other components like brake drums. rope drums, transmission systems etc. Example of situations where they are used are coupling a gearbox to an axle using a connecting shafts with flexible gear / rigid couplings.
To ensure effective sealing, plummer blocks are often available with a variety of special options and end covers. Benefits include a facility for easy mounting and dismounting of pre-assembled shafts, but this of course depends on the individual product.
Plummer block housings can be used with high-capacity spherical roller bearings or self-aligning ball bearings. They are manufactured from high-strength cast iron as standard but are also available in cast steel or spheroidal graphite cast iron. The housings have a re-lubrication facility and can be used with either oil or grease lubrication.